Bannerman Island: A History of the Man Behind the Castle

A word from Hudson Valley Magazine’s Executive Editor, Olivia J. Abel

Photo by John Morzen

For over a century, travelers on Metro-North’s Hudson line have been baffled and amused by the sight of a castle on a tiny island that flashes past their windows just south of Beacon. Here’s the fascinating story of the eccentric man who built it.

Bannerman’s Island Arsenal was constructed—though never finished—by an entrepreneurial Scotsman named Frank Bannerman. He was the biggest arms merchant in the United States—probably the world. There wasn’t a rifle, uniform, howitzer, sidearm, mortar, canteen, blanket, tomahawk, bayonet, machete, pith helmet, or suit of armor that he wouldn’t buy for a hundredth of a penny on the dollar. If he didn’t melt the metal down as scrap, he resold the stuff to just about anyone—from civilians who walked in off the street to Far East armies and banana republics. Sometimes he dealt with assumedly more sophisticated buyers; in 1917, he tried to sell the U. S. Navy 30 six-inch naval rifles for $450,000, which he’d bought for $78 each. (He lowered the price to $150,000 when several Congressmen threatened an investigation.)

Bannerman purchased everything he could that was left over from the Civil War. He bought 90 percent of all the arms and equipment seized by the U. S. after the Spanish-American War. When Sitting Bull was forced to surrender his tribe’s weapons, Bannerman bought the 50 rifles and carbines used at the Battle of the Little Bighorn in 1876, some still loaded. When material was salvaged from the battleship USS Maine, which exploded and ultimately sank in Havana Harbor, Cuba, in 1898, Bannerman, of course, bought it.

Bannerman castle
Photo by John Morzen

He established his business in New York in 1865, when he was only 15 years old, and eventually fancified his name as “Francis.” Bannerman essentially invented what used to be called the army-navy store, and his block-long, seven-floor shop on lower Broadway was half museum, half militaria collector’s paradise. To this day, the 300-page annual catalogues he issued are collectors’ bibles.

- Advertisement -

The catalogues are filled not only with wares but technical articles (“Some Problems of the Early Breech-Loaders,” by Major G. Tylden, British Army) and parts lists (“Vetterli Magazine-Musket, Swiss, 45 parts peculiar and essential to the system”). Thousands of items are for sale, and thousands of others ostensibly are not: “Articles shown without prices are not for sale but offered as reference only.” Which was probably code for, “Make me an offer I can’t refuse.”

@hudsonvalleymag Bannerman Island is a must-visit in the Hudson Valley! // #bannerman #bannermanisland #dutchesscounty #dutchesscountyny #hudsonvalley #hudsonriver #hudsonvalleyny #hvmag // Video @sabrina.sucato ♬ Lo-fi hip hop – NAO-K

By the turn of the century, Bannerman’s warehouses were so packed with ordnance that the city told him to store it somewhere else before he blew up Brooklyn. Some say he spotted the island during a weekend trip up the Hudson, others believe that his son, David, did while sailing with a friend. Either way, Bannerman discovered the tiny, unpopulated Pollopel Island, a forgotten dot of land near the east bank of the Hudson River. Plus, it was four miles north of the military academy at West Point. Perfect! By barge and by trainload, Bannerman’s stock was moved up the river and into a growing series of armories and magazines that he built on the island.

A transplanted Scot, Bannerman had a castle jones. During his buying trips to Europe and the British Isles, he never met a castle he didn’t like, so in 1901, he began building one on Pollopel. The design was inspired by a battlement he saw in Bavaria, an embrasure he liked from Scotland, a decorative pediment he eyed in Italy—a hodge-podge of castle cues that Walt Disney would have loved.

Frank Bannerman
Frank Bannerman VI, founder of Bannerman’s Arsenal. Photo courtesy of Bannerman Castle Trust, Inc.

Far from building a monument for the ages, Bannerman’s castle was more a piece of folk art that was crudely frosted with cement, built not by stonemasons and carvers but by local farmers and workmen. It was also a huge billboard. Bannerman whitewashed the castle walls that faced Hudson River excursion boats on one side, and the New York Central Railroad tracks on another. And on those walls, he emblazoned “Bannerman’s Island Arsenal” and the company’s Manhattan address in 4-foot-high letters.

- Partner Content -

Always looking for new markets, Bannerman did a brisk trade in otherwise-useless small fieldpieces that he sold to municipalities as mini-monuments for the town square or village green. If your neighbors gather around a “French 75” or “Civil War cannon” under the town flagpole every Memorial Day, it is likely they may have came from Bannerman & Sons. He also manufactured cheap, reconditioned sporting and military rifles by combining the best parts of broken-down guns that the company had in its arsenal—like rechambered Krag barrels, say, restocked with Springfield woodwork plus some Mauser parts and Lyman sights. Today, some collectors avidly seek these “Bannermans,” though few would dare fire one.

Ruination of the castle began in 1920, two years after Bannerman died. A black-powder explosion in a magazine blew out every window on the island, tumbled towers, threw a 25-foot piece of a building over a thousand feet of water to the New York Central tracks, blocking the line for a day. After his widow narrowly escaped death by vacating a hammock about to be buried under masonry, the island was increasingly abandoned to caretakers. One in particular, in the late 1950s when Bannerman’s Arsenal was finally “decommissioned” by an ex-Navy munitions expert, took a particularly rare Gatling gun and pounded it into shapelessness with a sledge, then sold it to a local scrapyard for beer money. Today, authentic Gatlings sell for as much as $200,000.

The castle was gutted by weather and vandals, and in 1969, a fire that raged for three days and nights pretty much finished the job. Today, Pollopel Island and the castle ruins are owned by New York State, and though access to the island was forbidden for many years, it was re-opened under the protection of the Bannerman Castle Trust in 2004.

Today, a variety of tours are available on weekend days from May to October. Most can be scheduled through the Trust’s website ( Some are guided walking tours after a riverboat ride from Newburgh or Beacon, others are kayak trips offered by Storm King Adventure Tours and Mountain Valley Guides, both in Cornwall. There is also the option of scheduling a tour using your own kayak or canoe for $40. Access from Newburgh or Beacon costs $40 for adults and $35 for children, including the boat ride. Kayak tours range from $100–$130 per person, kayak rental included. The Trust hosts seasonal concert and performance series, too.

Related: Explore the Hudson Valley Aboard These Riveting River Cruises

Our Digital Partners

Learn how to become a digital partner ...

Our Excellence in Nursing Awards take place on May 1!

Our Best of Hudson Valley ballot is open through March 31!

Unveiled: A Boutique Bridal Brunch is February 25!

Holiday flash sale ... subscribe and save 50%

Limited time offer. New subscribers only.